In packet data services of a GSM EDGE radio access network (GSM EDGE Radio Access Network, GERAN), due to a relatively independent uplink and downlink resource allocation mode, the uplink resource allocation is addressed by using an uplink state flag (Uplink State Flag, USF), and the downlink resource allocation is addressed by using a temporary flow identity (Temporary Flow Identity, TFI). The uplink resource allocation of a mobile station (Mobile Station, MS) is controlled by using the USF carried in a downlink data block, that is, a downlink data block sent by a network side of the communication system to the MS includes both USF information and downlink data information.
In the prior art, when a modulation and coding capability of a mobile terminal scheduled by the USF information is different from a modulation and coding capability of a mobile terminal corresponding to the downlink data information, a downlink data block is sent by using a modulation and coding scheme (Modulation and coding scheme, MCS) supported by a mobile terminal with a poorer modulation and coding capability. In case that the data information part can use a higher-order modulation mode than the USF part, this sending method loses the flexibility of higher-order modulation on the data information part, thereby reducing throughput of downlink data.